Scroll machines can be used to compress, expand or pump fluids and include two scroll members each of which has a circular end plate and a spiral or involute wrap. The scroll members are maintained angularly and radially offset so that both wraps interfit to make either a plurality of line contacts or are spaced by minimum clearances between the wraps to thereby define at least one pair of fluid pockets or chambers. One scroll member is stationary and the other orbits through an eccentric shaft and an antirotation coupling. The relative orbital motion of the two scroll members shifts the line contacts or minimum clearances along the curved surfaces of the wraps so that the trapped volumes in the fluid pockets change in volume. The trapped volumes can increase or decrease depending upon the direction of orbiting motion. Because several trapped volumes generally exist at the same time, several line contact or minimum clearance points also exist at the same time with each moving along the wraps with movement being towards the center or discharge port in the case of a compressor. In the case of a compressor, the compressed gas produces a force tending to axially separate the scroll members resulting in high thrust loads and tip leakage. Additionally, different designs are normally required for horizontal and vertical units. The inherent configuration of scroll machines is tall/long and thin. Thus, from the system unit size and packaging configurations, it is generally desirable to mount the scroll machines horizontally.
Conventionally, in vertical scroll compressors, the motor is mounted beneath the scroll mechanism with the following results: a slightly longer shell; a basic centrifugal pump which requires high lift in order to cross the motor and lubricate the highly loaded bearings; a gravity oil separation mechanism which is orientation sensitive to return the oil to the sump: and a finely metered oil injection system with limited sealing capabilities.